1. Field of the Invention
The present invention relates to an image processing apparatus for performing an image adjusting process, image processing method, and image processing program thereof.
2. Description of the Related Art
Conventionally, an image processing apparatus which applies an adjusting process to an image is known. For example, the edge of an image optically scanned by a scanner of a copying machine is more blurred than that of the original document image, and an image with poor sharpness is obtained when it is printed on a print medium intact. Upon applying an edge emphasis filter as an edge emphasis process after scanning for the purpose of enhancing the sharpness, an unnatural image is formed since the character edge is emphasized too strongly due to so-called overshoot or undershoot. Also, with this process, noise and moiré generated upon scanning are emphasized. In order to solve these problems, a technique that substitutes the pixel of interest by surrounding pixels is proposed (Japanese Patent No. 2620368).
However, with the aforementioned prior art, if there are multicolor image signals, appropriate adjusting means cannot be provided. For example, with the technique described in Japanese Patent No. 2620368, if a discrimination process is executed based on the distribution pattern of image signals independently for each of a plurality of colors, image emphasis signals suited to a color image cannot be generated, resulting in color misregistration.
Furthermore, upon checking the distribution pattern of image signal, if a large filter size is used, the calculation volume increases, resulting in an increase in volume of a process for generating an poorly defined signal.